This disclosure relates to an optoelectronic circuit and more specifically to a combination of microwave and photonic components for a compact, self contained Mach-Zehnder interferometer (MZI) modulator.
Modulation of an optical signal at microwave frequencies, typically above 10 GHz, requires external modulation of a laser source to prevent unintentional modulation of the laser frequency (e.g. chirping). Towards this end, a Mach-Zehnder interferometer structure is often employed to create an optical phase and/or amplitude modulator. One or both arms of the Mach-Zehnder interferometer contains electrodes to permit phase modulation of an optical signal via the electro-optic effect. These electrodes require a drive amplifier to supply adequate electric field to produce the electro-optic effect. The amplifier requires sufficient bandwidth and output capability to drive the reactive load presented by the Mach-Zehnder electrodes.
Early electro-optic (EO) modulators required a large external power amplifier to provide hundreds of volts to produce the electro-optic effect. Recent devices have the modest drive requirement of 8-12 volts, but still require an external RF power amplifier to operate. Advances in polymer technology have allowed for the development of materials with large EO figures of merit, resulting in low Vxcfx80 numbers.
An embodiment of the invention is a method of fabricating an integrated optoelectronic circuit. The method includes positioning a microchip on a first flexible dielectric substrate. A polymer electro-optic waveguide is positioned on or within the first flexible dielectric substrate. A ground electrode is positioned along the electro-optic waveguide. A signal electrode is positioned along the electro-optic waveguide opposite the ground electrode. A first patterned metallization layer is applied to the first flexible dielectric substrate. A second flexible dielectric substrate is positioned along the first flexible dielectric substrate. A plurality of via openings are provided in the first and second flexible dielectric substrates. A second patterned metallization layer is applied to the second flexible dielectric substrate.